The subject invention is directed to a system and method for printing of color images. Transforming RGB values into CMYK values suitable for a color laser printer is often done using a 3-dimensional look-up table (LUT). However, this requires significant processing of the data for the interpolation. The system presented herein teaches a color rendering scheme which is particularly advantageous in reducing color conversion processing demands in a displayed or printed image.
In printers, such as in color ink jet and color laser printers, conversions of RGB values to printer colorant values requires considerations of the attributes of the printer's colorants, such as unwanted absorptions, absence of perfect additivity and proportionality, and the like. One way of providing the color conversion from input RGB to output CMYK values is to use simple matrix multiplication. In the past, this was accomplished with a common practice of applying a masking equation that adjusts an image for better reproduction. Such masking equations are typically are a set of linear formulas, the strength of which determines the degree of color correction. In a typical system, a mask is either preset for a printer or fixed for an image for uniform application to each pixel forming that image.
While such image corrections are advantageous for attributes, such as enabling very fast color conversions which compensate for the unwanted absorptions of colorants or additivity and proportionality of color, as noted above, such schemes are prone to clipping of colors which have higher degrees of color saturation. The resultant transformation to the printer or output device color output results in a loss in an ability to accurately reproduce these high colors and the visible result will be undesirable hue shifts and clipping of colors.
It would be desirable to have a color correction system which functions to eliminate or minimize clipping of color values at or near the saturation level while simultaneously maintaining image quality and contrast. The subject invention solves these problems, and others, and provides a system and method for applying a variable saturation scheme that is readily and inexpensively provided with color printing systems.